It is known to use optical instruments for splicing or bonding optical fibres, for instance instruments such as cameras equipped with microscope objectives, to determine the relative offset of and the distance between the fibre ends, computers provided with display screens for monitoring and controlling the fibre splicing process, means for adjusting and setting the positions of the fibre ends, and means for fusing the fibre ends together. When the camera is coupled to the computer via an image transmitter, an enlarged image of the fibre ends can be produced on the computer screen and the correct distance and offset between the fibre ends with respect to fibre material and dimensions can be adjusted automatically, so as to obtain a splice that has optical properties. Subsequent to having aligned the fibres and set the distance between the fibre ends, the fibre ends may be fused together with the aid of a light arc generated with the aid of high-voltage electrodes, so as to form an homogenous splice.
U.S. Pat. No. 5,323,225 discloses a method of determining the positions of transverse axes of an optical fibre that has an elliptical core. The fibre is illuminated with coherent light such as to produce an interference pattern which, when studied, is able to disclose optimal positioning of the fibre ends for obtaining a correct fibre bond or splice.